Set easyDMA

RE: Set easyDMA

Petter Myhre — Thu, 24 Nov 2016 15:01:37 GMT

Correct :)

RE: Set easyDMA

User1321 — Thu, 24 Nov 2016 14:55:19 GMT

So basically TWI itself works the same with easyDMA enabled or not, the difference comes from where TWI is reading/writing the data when TWI is transmitting/receiving? Is this correct? Then, easyDMA is very useful only when we are dealing with the RAM of the nrF52, NOT related with the memory of, for example, a sensor that I have connected to the nordic Microcontroller. Thanks again

RE: Set easyDMA

Petter Myhre — Thu, 24 Nov 2016 14:36:00 GMT

Usually the CPU configures the TWI peripheral and starts an operation, then goes to sleep. If it is a TX operation, EasyDMA can be used by TWI to read the data directly from RAM, while the CPU is sleeping. If it is an RX operation, EasyDMA can be used by TWI to write the data directly to RAM, while the CPU is sleeping. After an operation is complete, the TWI can trigger an interrupt to wake the CPU to take appropriate action.

RE: Set easyDMA

User1321 — Thu, 24 Nov 2016 14:16:04 GMT

Thank you for your answer Peter, I have still one doubt. Can I use easyDMA for reading or writing data from a sensor using EasyDMA while the CPU is sleeping?Or it can be used only for writing/reading from the RAM? This is actually the reason of why I am thinking on using easyDMA. Thanks again

RE: Set easyDMA

Petter Myhre — Thu, 24 Nov 2016 10:04:18 GMT

For Setting the easyDMA on I2C, Do I need just to set the TWI0_USE_EASY_DMA to 1 ?

If you are using the TWI driver, yes.

Also do I need to set an arrayList? which?

No.

or can I just use the same settings that I use for TIW as a regular TWI transmission, if this is the case: what is the difference that it has when I use easyDMA wrt I2C?

The same settings. EasyDMA allows peripherals to access RAM directly. See this for more information.

Is there any API for using easyDMA? or maybe an example?

This is an example.

In the case that I want to save data on the RAM, is easyDMA the only way of doing it?

If you want the peripheral to save data directly to RAM, yes. The CPU can of course read data from a peripheral and write it to RAM.